The present invention is based on Japanese Patent Application No. 2000-341913, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a cable guide structure for a window regulator, and more specifically to a cable guide structure for a window regulator having pulleys, which are rotatably provided at end portions of two rails and guide a cable looped thereover like a X-shape.
2. Description of the Related Art
Hitherto, there has been known a cable window regulator W of a configuration in which a window panel P is moved up and down by setting a loop consisting of cables R, which is endlessly guided over a pair of pulleys 101 and 101a respectively mounted on top and bottom portions of a front-side rail 100 and over a pair of pulleys 103a and 103 respectively mounted on top and bottom portions of a rear-side rail 102, so that the cables R extend along the rails 100 and 102 and wind around the pulleys 101, 103, 103a and 101a and cross each other like a X-shape, as illustrated in FIG. 6. Such rails 100 and 102 are formed in such a manner as to be laterally curved along an outer panel (not shown) of a door F, as viewed in this figure. Pulley mounting surfaces 10a and 102a respectively provided at the top portion of the rail 100 and the bottom portion of the rail 102 are inclined to an imaginary linear reference plane connecting the top portion of the rail 100 and the bottom portion of the rail 102 to each other. Moving elements 104 and 106 support the window panel P and are respectively provided on the rails 100 and 102 in such a way as to freely move up and down.
Here, parts 105 of the loop consisting of the cables R are respectively arranged between a pair of pulleys 101 and 101a and between a pair of pulleys 103 and 103a and referred to as rail cabling portions. Moreover, another part 107 of the loop consisting of the cables R is linearly arranged between the pulley 101 disposed at the top portion of the front-side rail 100 and the pulley 103 disposed at the bottom portion of the rear-side rail 102, and referred to as a first diagonally cabling portion. Furthermore, another part 108 of the loop consisting of the cable R is slacked and arranged between the pulley 101a provided on the bottom portion of the front-side rail 100 and referred to as a second diagonally cabling portion. A drive unit K is connected to a halfway part of the second diagonally cabling portion 108.
However, as illustrated in FIG. 7, the first diagonally cabling portion 107 is linearly arranged in such a conventional structure, as described above. Thus, the first diagonally cabling portion 107 is arranged so that the direction of an axis thereof differs from a guiding direction extending along each of the planes of rotation of the pulleys 101 and 103. Thus, there are fears that the first diagonally cabling portion 107 of the cable R comes in contact with each of edge portions of cable guide grooves 109 and 111 of the pulleys 101 and 103, and that the durability of the cable R is lowered owing to the contact therebetween.
Moreover, there is a fear that the contact between the cable R and each of the edge portions of the cable guide grooves 109 and 111 causes a falling force to act upon the pulleys 101 and 103 thereby to generate resistance between the pulleys 101, 103 and shafts respectively supporting these pulleys.
The invention is accomplished in view of such problems of the conventional techniques. Accordingly, an object of the invention is to provide a cable guide structure for a window regulator, in which the guiding direction of each of cable guide grooves of pulleys is set in such a way as to coincide with the direction of an axis of a diagonally cabling portion, which is a linearly arranged part of a cable, thereby to enhance the durability of the pulleys and the cable without generating resistance between the cable and each of the pulleys even when the diagonally cabling portion is linearly arranged.
To achieve the foregoing object, according to the invention, there is provided a cable guide structure (hereunder referred to as a first cable guide structure) for a window regulator, which comprises moving elements for supporting a window panel, which are upwardly and downwardly slidably mounted on rails that are provided in such a way as to be parallel with each other and are each laterally curved and each extend upwardly and downwardly, cables, which are respectively connected to top and bottom portions of each of the moving elements and also connected to a drive unit and each have a rail cabling portion, which is extended along a corresponding one of the rails, and a diagonally cabling portion so that the diagonally cabling portions of the cables cross each other like a X-shape between the rails, and pulleys each having a cable guide groove, which is formed in a circumferential portion thereof, for guiding the cable. The pulleys are rotatably mounted on the mounting surface of the top portion of one of the rails and that of the bottom portion of the other rail. In this structure, the diagonally cabling portion of at least one of the cables is linearly arranged. Further, a direction of a tangent line, which extends along a plane of rotation of a corresponding one of the pulleys, at a contact point between the rail cabling portion of each of the cables is set in such a manner as to coincide with a direction of an axis of the rail cabling portion of a corresponding one of the rails. Furthermore, a direction of a tangent line, which extends along a plane of rotation of a corresponding one of the pulleys, at a contact point between the linearly and diagonally cabling portion of the cable and the cable guide groove of the corresponding one of the pulleys is set in such a manner as to coincide with a direction of an axis of the linearly and diagonally cabling portion of the cable.
According to the first cable guide structure of the invention, the guiding direction of the cable guide groove of the pulley coincides with the direction of an axis of the rail cabling portion of the cable. Moreover, the guiding direction of the cable guide groove of the pulley coincides with the direction of an axis of the linearly and diagonally cabling portion of the cable. Thus, the cable is let out only along the guiding direction of the cable guide groove. Consequently, the cable is prevented from coming in contact with the edge portion of the guide groove of the pulley. Moreover, wear is prevented from occurring on the edge portion. Further, the cables are not curved by the edge portions of the pulleys. Thus, the durability of the window regulator is enhanced. Furthermore, the cables do not touch the edges of the pulleys. Thus, the resistance generated between the pulleys and the shafts respectively supporting the pulleys is reduced. Moreover, a simple structure, according to which the pulleys are only inclined, enables the reliable guiding of the cables each having the arranging and cabling portions that are arranged in directions different from the direction along the planes of rotation of the pulleys. Consequently, the window regulator is simplified. Moreover, the diagonally cabling portion is linearly arranged between the pulleys. This enables the arrangement of the cable by using the shortest length thereof. Consequently, the cost of materials is reduced.
According to an embodiment (hereunder referred to as a second cable guide structure) of the first cable guide structure of the invention, the diagonally cabling portion of the cable is covered with an outer tube, both end portions of which are fixed to the rails.
According to the second cable guide structure of the invention, the diagonally cabling portion of the cable is covered with the outer tube, both end portions of which are fixed to the rails. Thus, the rails are connected to each other by the outer tube. Even before the window regulator is assembled to the door, the window regulator is integrated. Consequently, the management of components is facilitated. The assembling of the window regulator to the door is achieved only by assembling the integrated window regulator to the door. Thus, the assembling workability is improved.